PIC18F23K20 MICROCHIP [Microchip Technology], PIC18F23K20 Datasheet - Page 183

• Manufacturer Part Number: PIC18F23K20
• Description: 28/40/44-Pin Flash Microcontrollers with nanoWatt XLP Technology
• Manufacturer: MICROCHIP [Microchip Technology]

16.4.4
The PWM mode supports an Auto-Shutdown mode that
will disable the PWM outputs when an external
shutdown event occurs. Auto-Shutdown mode places
the PWM output pins into a predetermined state. This
mode is used to help prevent the PWM from damaging
the application.
The auto-shutdown sources are selected using the
ECCPAS<2:0> bits of the ECCP1AS register. A
shutdown event may be generated by:
• A logic ‘0’ on the FLT0 pin
• Comparator C1
• Comparator C2
• Setting the ECCPASE bit in firmware
REGISTER 16-2:
 2010 Microchip Technology Inc.
bit 7
Legend:
R = Readable bit
-n = Value at POR
bit 7
bit 6-4
bit 3-2
bit 1-0
ECCPASE
R/W-0
ENHANCED PWM
AUTO-SHUTDOWN MODE
ECCPASE: ECCP Auto-Shutdown Event Status bit
1 = A shutdown event has occurred; ECCP outputs are in shutdown state
0 = ECCP outputs are operating
ECCPAS<2:0>: ECCP Auto-shutdown Source Select bits
000 = Auto-Shutdown is disabled
001 = Comparator C1OUT output is high
010 = Comparator C2OUT output is high
011 = Either Comparator C1OUT or C2OUT is high
100 = V
101 = V
110 = V
111 = V
PSSACn: Pins P1A and P1C Shutdown State Control bits
00 = Drive pins P1A and P1C to ‘0’
01 = Drive pins P1A and P1C to ‘1’
1x = Pins P1A and P1C tri-state
PSSBDn: Pins P1B and P1D Shutdown State Control bits
00 = Drive pins P1B and P1D to ‘0’
01 = Drive pins P1B and P1D to ‘1’
1x = Pins P1B and P1D tri-state
ECCPAS2
R/W-0
ECCP1AS: ENHANCED CAPTURE/COMPARE/PWM AUTO-SHUTDOWN
CONTROL REGISTER
IL
IL
IL
IL
on FLT0 pin
on FLT0 pin or Comparator C1OUT output is high
on FLT0 pin or Comparator C2OUT output is high
on FLT0 pin or Comparator C1OUT or Comparator C2OUT is high
W = Writable bit
‘1’ = Bit is set
ECCPAS1
R/W-0
ECCPAS0
R/W-0
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
PSSAC1
R/W-0
A shutdown condition is indicated by the ECCPASE
(Auto-Shutdown Event Status) bit of the ECCP1AS
register. If the bit is a ‘0’, the PWM pins are operating
normally. If the bit is a ‘1’, the PWM outputs are in the
shutdown state.
When a shutdown event occurs, two things happen:
The ECCPASE bit is set to ‘1’. The ECCPASE will
remain set until cleared in firmware or an auto-restart
occurs (see Section 16.4.5 “Auto-Restart Mode”).
The enabled PWM pins are asynchronously placed in
their shutdown states. The PWM output pins are
grouped into pairs [P1A/P1C] and [P1B/P1D]. The state
of each pin pair is determined by the PSSAC and
PSSBD bits of the ECCP1AS register. Each pin pair may
be placed into one of three states:
• Drive logic ‘1’
• Drive logic ‘0’
• Tri-state (high-impedance)
PIC18F2XK20/4XK20
PSSAC0
R/W-0
x = Bit is unknown
PSSBD1
R/W-0
DS41303G-page 183
PSSBD0
R/W-0
bit 0